DNSBL Stands for “Domain Name System Blacklists”, also known as DNSBL’s or DNS Blacklists, are spam blocking lists that allow a website administrator to block messages from specific systems that have a history of sending spam. As their name implies, the lists are based on the Internet’s Domain Name System, which converts complicated, numerical IP address such as 18.104.22.168 into domain names like example.net, making the lists much easier to read, use, and search. If the maintainer of a DNS Blacklist has in the past received spam of any kind from a specific domain name, that server would be “blacklisted” and all messages sent from it would be either flagged or rejected from all sites that use that specific list.
A domain name system based list (DNSBL) is an anti-spam technique used to track IP addresses that send spam. DNSBL is a database of IP addresses that includes the addresses of known spammers, open relays, proxy servers, and computers compromised by crackers and malicious code, also known as zombie computers. Emails sent from addresses included in the DNSBL are rejected from all sites that use the list.
What is SPFBL
SPFBL is a Brazilian blacklist that primarily focuses on reducing the volume of Brazilian spam. It was created in late 2015 and was opened up for use by any MTAs to block spam sources and IPs unsuitable for sending mail.
SORBS Database Entry Check
The SORBS (Spam and Open Relay Blocking System) provides free access to its DNS-based Block List (DNSBL) to effectively block email from more than 12 million host servers known to disseminate spam, phishing attacks and other forms of malicious email. The list typically includes email servers suspected of sending or relaying spam, servers that have been hacked and hijacked, and those with Trojan infestations. In an attempt to provide preemptive protection, SORBS also lists servers with dynamically allocated IP addresses.